Hard disk drives are used in almost all computer system operations. In fact, most computing systems are not operational without some type of hard disk drive to store the most basic computing information such as the boot operation, the operating system, the applications, and the like. In general, the hard disk drive is a device which may or may not be removable, but without which the computing system will generally not operate.
The basic hard disk drive model was established approximately 50 years ago and resembles a phonograph. That is, the hard drive model includes a storage disk or hard disk that spins at a standard rotational speed. An actuator arm with a suspended slider is utilized to reach out over the disk. The arm carries a head assembly that has a magnetic read/write transducer or head for reading/writing information to or from a location on the disk. The complete head assembly, e.g., the suspension and head, is called a head gimbal assembly (HGA).
In operation, the hard disk is rotated at a set speed via a spindle motor assembly having a central drive hub. Additionally, there are tracks evenly spaced at known intervals across the disk. When a request for a read of a specific portion or track is received, the hard disk aligns the head, via the arm, over the specific track location and the head reads the information from the disk. In the same manner, when a request for a write of a specific portion or track is received, the hard disk aligns the head, via the arm, over the specific track location and the head writes the information to the disk.
Over the years, the disk and the head have undergone great reductions in their size. Much of the refinement has been driven by consumer demand for smaller and more portable hard drives such as those used in personal digital assistants (PDAs), MP3 players, and the like. For example, the original hard disk drive had a disk diameter of 24 inches. Modern hard disk drives are much smaller and include disk diameters of less than 2.5 inches (micro drives are significantly smaller than that). Advances in magnetic recording are also primary reasons for the reduction in size.
However, the decreased track spacing and the overall reduction in HDD component size and weight have resulted in problems with respect to the electrical lead suspension (ELS). Specifically, as the component sizes shrink, the conductive portions begin to move closer together both horizontally and vertically. As the conductive portions, e.g., electric traces, solder connections, layered components and the like, move closer to one another the conductive portions begin to interact negatively with one another. For example, there may be times of cross talk wherein one of the traces becomes electrically coupled with another of the traces or impedance issues when the layers form a parallel plate capacitor. In general, an ELS may be formed by a subtractive process, such as, e.g. an Integrated Lead Suspension (ILS), an additive process, such as, e.g., a Circuit Integrated suspension (CIS) or as a Flex-On Suspension (FOS) when the FOS is attached to a base metal layer, or it may be a Flex Gimbal Suspension Assembly (FGSA) that is attached to a base metal layer, or any form of lead suspension used in a DASD.
One solution to the problem of cross talk and the other disruptive interactions has been to lower the power requirements of the conductive portions. However, the power requirements can only be reduced to a minimum level. After the minimum operating level of the HDD is reached, no further power reduction can be realized without adversely affecting the operation of the HDD.